Sökning: "transformer"

Visar resultat 6 - 10 av 116 avhandlingar innehållade ordet transformer.

1. 6. Electromagnetic Modelling of Power Transformers for Study and Mitigation of Effects of GICs

   Författare :Seyedali Mousavi; Göran Engdahl; Ebrahim Rahimpour; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; transformer; hysteresis; DC magnetization; GMD; GICs; FEM; reluctance network method; low frequency transients; core losses; winding losses; eddy current losses; transformator; hysteresis; DC; likströmsmagnetisering; GMD; GIC; FEM; reluktansnätverksmodell; lågfrekventa transienter; kärnförluster; lindningsförluster; virvelströmsförluster; Electrical Engineering; Elektro- och systemteknik;

   Sammanfattning : Geomagnetic disturbances that result from solar activities can affect technological systems such as power networks. They may cause DC currents in power networks and saturation of the core in power transformers that leads to destruction in the transformer performance. LÄS MER

3. 7. Electromagnetic Modelling of Power Transformers with DC Magnetization

   Författare :Seyed Ali Mousavi; Göran Engdahl; S. V. Kulkarni; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Transformer; Hysteresis; DC magnetization; GICs; FEM; reluctance network method;

   Sammanfattning : DC currents that flow through the ground can be injected to the star windings of power transformers from their grounded neutral points and close their path with transmission lines. The geomagnetically induced currents (GICs) and AC/DC convertors of high voltage direct current (HVDC) systems are the sources of such DC currents. LÄS MER

4. 8. Process Control and Simulation of Ferromagnetic Strip in the Power Transformers and Electrical Machines Applications : Electric power systems

   Författare :Kourosh Mousavi Takami; Jafar Mahmoudi; Örjan Danielsson; Mihai Nicolescu; Mälardalens högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Strip; electrical machines; transformer; cold rolling mills; process; automation; control; Band; elektriska maskiner; transformatorer; kallvalsningsverk; processautomation; reglerteknik; Electric power engineering; Elkraftteknik; Energy- and Environmental Engineering; energi- och miljöteknik;

   Sammanfattning : This thesis investigates optimization of the control of electrical and thermal equipment by using FEM and CFD modeling in combination with dynamic simulation models. The thesis focuses on the production of electrical strips and the control system with the aim of reducing losses and improving magnetic properties. LÄS MER

5. 9. Partial Discharge Signatures of Defects in Insulation Systems Consisting of Oil and Oil-impregnated Paper

   Författare :Mohamad Ghaffarian Niasar; Hans Edin; Peter Werelius; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; partial discharge; transformer; oil; ageing; temperature; PD classification;

   Sammanfattning : Partial discharge measurement is a common method for monitoring and diagnostics of power transformers, and can detect insulation malfunctions before they lead to failure. Different parameters extracted from the measured PD activity can be correlated to the PD source, and as a result it is possible to identify the PD source by analyzing the PD activity. LÄS MER

7. 10. A lumped element transformer model including core losses and winding impedances

   Författare :David Ribbenfjärd; Göran Engdahl; Arvid Broddefalk; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; power transformer; hysteresis; dynamic hysteresis; eddy currents; excess eddy currents; leakage flux; winding model; core model; magnetic measurements; magnetic materials; Electrical engineering; Elektroteknik;

   Sammanfattning : In order to design a power transformer it is important to understand its internal electromagnetic behaviour. That can be obtained by measurements on physical transformers, analytical expressions and computer simulations. LÄS MER